A wide area network (WAN) can connect a local area network (LAN) established by an Internet service provider (ISP) to a data center outside of the LAN. A WAN may employ network appliances and content delivery networks (CDNs) as cache systems to reduce the likelihood of network traffic causing bottlenecks at the data centers. The cache systems can store popular content, e.g., a video or photo that is requested by many users in locations that are closer to the users than the data centers, in terms of geographic distance, network distance (“hops”) or both. A “cache hit” occurs when requested data can be found in a cache, whereas a “cache miss” occurs when it cannot. Having a high cache “hit rate” lowers the latency of delivering the content to the user and also reduces the bandwidth requirement because the requested data has to travel a smaller distance than from the data center.
Having network appliances and CDNs as close as possible to end users can significantly speed up network communication and reduce network congestion. However, network appliances and CDNs are expensive because they tend to utilize computationally powerful devices because they implement highly complex caching algorithms and potentially provide service to a very large number of end-user devices. The network appliances and the CDNs require powerful computing devices with high network throughput, high processing power, high hardware and operating system reliability, and a large amount of memory (e.g., both system memory and persistent memory). These requirements make it difficult to implement the network appliances and the CDNs near “extreme” network-edges of the WAN (e.g., closer to end-user devices than traditional network appliances and CDNs). That is, there are usually insufficient resources (capital and/or technological) to implement that many high-complexity computing systems in every remote location that may have an end-user.
The figures depict various embodiments of this disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of embodiments described herein.